Chap. XI. SUMMAEY ON INSECTS. 421 



Sexual selection implies that the more attractive 

 individuals are preferred by the opposite sex ; and as 

 with insects, when the sexes differ, it is the male which, 

 with rare exceptions, is the most ornamented and 

 departs most from the type to which the species 

 belongs ; — and as it is the male which searches eagerly 

 for the female, we must suppose that the females habit- 

 ually or occasionally prefer the more beautiful males, 

 and that these have thus acquired their beauty. That 

 in most or all the orders the females have the power 

 of rejecting any particular male, we may safely infer 

 from the many singular contrivances possessed by the 

 males, such as great jaws, adhesive cushions, spines, 

 elongated legs, &c, for seizing the female ; for these 

 contrivances shew that there is some difficulty in the 

 act. In the case of unions between distinct species, 

 of which many instances have been recorded, the 

 female must have been a consenting party. Judging 

 from what we know of the perceptive powers and 

 affections of various insects, there is no antecedent im- 

 probability in sexual selection having come largely into 

 action ; but we have as yet no direct evidence on this 

 head, and some facts are opposed to the belief. Never- 

 theless, when we see many males pursuing the same 

 female, we can hardly believe that the pairing is left to 

 blind chance — that the female exerts no choice, and 

 is not influenced by the gorgeous colours or other 

 ornaments, with which the male alone is decorated. 



If we admit that the females of the Homoptera and 

 Orthoptera appreciate the musical tones emitted by their 

 male partners, and that the various instruments for this 

 purpose have been perfected through sexual selection, 

 there is little improbability in the females of other 

 insects appreciating beauty in form or colour, and con- 

 sequently in such characters having been thus gained 



